Pressure indicating device



Aug- 5, 1958 L. BODDY 2,846,549

PRESSURE INDICATING DEVICE Original Filed Aug. 5, 1949 yUnited StatesPatent O PRESSURE INDICATING DEVICE Leonard Boddy, Ann Arbor, Mich.,assignor to King- Seeley Corporation, Ann Arbor, Mich., a corporation ofMi an application August 5, 1949, Serial No. 108,773. Divided and thisapplication December 20, 1954, Serial No. 476,506

7 Claims. (Cl. 201-48) This invention relates to current modulatingdevices and more particularly to variable-impedance pressure measuringdevices.

The object of this invention is to improve the accuracy and consistencyof performance of pressure-sensitive devices. p

A feature of thisinvention is an improved means for varying the value-ofa resistance as a function of the motion of a diaphragm.

Another feature of this invention is an improved variable resistancecontact element.

The manner of accomplishment of the foregoing object, the nature of theforegoing features, and other objects and features of the invention, maybe perceived from the following detailed description of embodiments ofthe invention when read with reference to the accompanying drawings inwhich: -f

Figure l is a top plan view of a pressure-sensing device embodying theprinciples of the present invention;

Fig. 2 is a sectional view taken substantially along the line 2-2 ofFig. l; and

Fig. 3 is a sectional view taken substantially along the line 3--3 ofFig. 2.

This application is a division of my application Serial No. 108,773,filed August 5, 1949. relating to Electrical Control Apparatus. Thatpatent application issued as Patent No. 2,835,885 on May 20, 1958, withcertain of the subject matter of that application being presented as acontinuation application, Serial No. 658,888, filed May 13, 1957.

In general electrical systems are sometimes employed to indicate orgauge fluid pressures, particularly in the gauging of, for example, theoil pressure in an automobile engine. To this end, gauging systems havebeen devised which include a voltage source, the output of which ispreferably reasonably closely regulated, an electrical gauge, and aresistor, the value of which varies as a function of the fluid pressure,for controlling'the ilow of current through the gauge. The gauge per semay be electromagnetic or electrothermal in nature.

Exemplary types of such gauging systems are disclosed in detail in theabove-identified application and reference may be made thereto for afull understanding of an appropriate use for the variable-resistancedevice herein disclosed.

Referring now to the drawings, the discclosed fluid pressure responsiveunit comprises a threaded tubular body 210, having a bore 212 which maybe and preferably is provided with a restricted section 214. Body 210is, of course, adapted to be threaded into the oil system of theassociated vehicle so that the bore 212 is in communication with thepressure fluid. Body 210 also serves as a grounding connection for theresistor 68. Body 210 is fixed to a dished circular member 216 whichcarries the previously mentioned flexible diaphragm 62. Diaphragm 62 isclamped between member 216, and a downwardly presenting cup-shapedspring housing member 220, which is assembled to the member 216 byinwardly turning the 2,846,549 Patented Aug. 5, 1958 ICC terminal flangethereof as indicated at 222. A coil spring 224 is caged between the baseof member 220 and the base of an upwardly presenting spring cup 226. Cup226 also carries a cup-shaped crank operating member 228, the uppersurface of which has direct sliding contact with the reversely bent end230 of crank 64. Preferably, the upper surface of member 228 is groundor otherwise finished to minimize the frictional resistance of thissliding movement.

Downwardly turned fingers 221 on member 220 and the rim 227 of cup 226act as locators for spring 224. The rim 227 of cup 226 also acts as alimit stop for cup 226.

Preferably and as illustrated, the crank 64 is formed of a continuouslength of rodlike stock, the intermediate body portion 234 of which isstraight, and is rotatably journaled in spaced bearings 236 and 238carried by member 220. One end of the straight body portion 234 isjoined to the operating end 230, by the rebent portion 240. The otherend of the straight portion 234 is joined to the contact operating end242 by similarly rebent portions 244.

With the foregoing arrangement, it will be appreciated that the flexiblediaphragm 62 serves simply as a fluidtight seal between the bore 212 andthe interior of the spring housing 220. Spring 224 continuously urgesthe spring 226 and element 228 downwardly. Crank 64 is provided with atorsion spring 246 which causes it to fol low the downward movements ofelement 228. Fluid pressures introduced through the bore 212, of course,urge element 228 upwardly against the force of spring 224 and any suchupward movements cause a corresponding up ward movement of crank 64. Theposition of the crank 64 is, therefore, at all times a measure of thetluid pressure acting on the oil below the diaphragm 62.

The operating end 242 of crank 64, carries the previously identifiedcontact 66 which has rubbing contact with the arcuately formed resistor68. Contact 66 is, of course, grounded to the casing and body 210through crank 64, spring 246, spring 224, member 220, and disk 216.Resistor 68 is wound on a mounting member 258, of arcuate form. Member250 is held in place by an arcuate support 252 which forms one wall ofan auxiliary housing member side wall portions 254 and 256. The sidewall portions are provided with laterally turned notched feet 258,through which tongues 260 struck from the body of the spring housing 220extend to secure the members in place. The upper end of the resistor 68i electrically connected to the mounting stud 262, which it otherwiseinsulated from the housing structure. The lower end of resistor 68 mayeither be insulated from or grounded to the casing and the body 210. Theouter casing 264 has a flared base 266, and is secured in place byinwardly turning the marginal flange portion 268 thereof. A nut 270threaded on the terminal stud 262 completes the assembly. Preferably andas illustrated, the interior of the outer casing 264 is vented asindicated at 272. This vent may be and preferably is of the type that isself sealing in the event the associated liquid, such as oil, comes incontact therewith. Thus, if the diaphragm 218 fails, and therebyintroduces a possibility of leakage through the unit, vent 272automatically seals itself olf, preventing this failure from causing aloss of the liquid.

While it will be apparent that the embodiment of the invention hereindisclosed is well calculated to fulfill the objects above stated, itwill be appreciated that the invention is susceptible to modification,variation and change without departing from the proper scope or fairmeaning of the subjoined claims.

, What is claimed is:

` l. A fluid pressure responsive current modulating means comprising acup-shaped member, a flexible diaphragm cover for said member, meansconnected to said member and defining a chamber one wall whereof isconstituted by said diaphragm, means defining a passage for admittingpressure uid to said chamber, a spring acting between the base of saidcup-shaped member and 5 said diaphragm, a cup-like retainer for the endof said spring which bears against said diaphragm, and variableresistance means having relatively tixed and movable parts, the movablepart being operatively responsive to movement of said spring retainer asinfluenced by pressures acting against said diaphragm.

2. In a current modulating device, a support surface, an actuatingmember, means for varying the position of said member relative to saidsupport surface as a function of sensed variations in a physicalcondition, a crank comprising a rod bent to define abody portion and twoarm portions, bearing means supported upon said support/ surface andsurrounding a portion of said body portion@y for supporting said bodyportion for rotational motion prising a rod bent to define a bodyportion and two arm 3 portions disposed at opposite ends of said bodyportion and extending at angles to the longitudinal axis thereof,bearing means supported upon said support surface and surrounding aportion of said body portion for supporting said body portion forrotational motion about an axis passing through said body portion, meansincluding one of said arm portions for rotating said body portion underthe control of said actuating member, a resistor, and

' means including the other one of said arm portions movable by saidbody portion for varying the effective resist- 40 ance value of saidresistor, said other arm portion being bendable to adjust therelationship between said contact and said resistor at a selectedposition, said one arm portion being bendable to adjust the relativeamplitudes of motion of said contact and said actuating member.

4. A fluid pressure responsive current modulating means comprising acup-shaped member, a flexible diaphragm cover for said member, meansconnected to said member and defining a chamber one wall whereof isconstituted by said diaphragm, means defining a passage for admittingpressure fluid to'said chamber, a spring acting between the base of saidcup-shaped member and said diaphragm, a cup-like retainer for the end ofsaid spring which bears against said diaphragm, a resistance element, acontact engaging said element, a crank member actuated by said springretainer, and resilient means connecting said contact to said crankmember.

5. A uid pressure responsive current modulating means comprising acup-shaped member, a exible diaphragm cover for said member, meansconnected to said no member and defining a chamber one wall whereof isconstituted by said diaphragm, means defining a passage for-admittingpressure uid to said chamber, a spring acting between the base of saidcup-shaped member and said diaphragm, a cup-like retainer for the end ofsaid spring which bears against said diaphragm, a resistance element, acontact engaging said element, a crank member actuated by said springretainer, and resilient means connecting said contact to said crankmember, said resilient means comprising a pair of spring armsinterconnected by a cross-member, means connecting said cross-member tosaid'crank, and means securing said contact tov said spring arms.

6. A- fluid pressure responsive current modulating means comprising acup-shaped member, a exible diaphragm cover for said member, meansconnected to said member and defining a chamber one wall whereof isconstituted by said diaphragm, means defining a passage for admittingpressure fluid to said chamber, a spring acting between the base of saidcup-shaped member and said diaphragm, a cup-like retainer for the end ofsaid spring which bears against said diaphragm, a crank comprising albody portion and two arm portions, means rotatably supporting said bodyportion, means including one of said arm portions for rotating said bodyportion under the control of said spring retainer, a resistor, and meansincluding the other one of said arm portions movable by said bodyportion for varying the effective resistance value of said resistor.

7. A uid pressure responsive current modulating means comprising acup-shaped member, a flexible diaphragm cover for said member, meansconnected to said member and defining a chamber one wall whereof isconstituted by' said diaphragm, means defining a passage for admittingpressure fluid to said chamber, a spring acting between the base of saidcup-shaped member and said diaphragm, a cup-like retainer for the end ofsaid spring which bears against said diaphragm, a crank c'ornprising abody portion and two arm portions, means rotatably supporting said bodyportion, means including one of said arm portions for rotating said bodyportion under the control of said spring retainer, a resistor, and meansincluding the other one of said arm portions movable by said bodyportion for varying the effective resist- 5 ance value of said resistor,said other arm portion being bendable to adjust the relationship betweensaid contactl and said resistor at a selected position, said one armportion being bendable to adjust the relative amplitudes of motion ofsaid contact and said spring retainer.

References Cited in the file of this patent UNITED STATES PATENTS2,226,441 Paul Dec. 24, 1940 2,243,807 Malone May 27, 1941 2,286,717Clason `iune 16, 1942 2,373,292 Clason Apr. 10, 1945 2,423,609 Middletonet al July 8, 1947 2,485,433 Crum Oct. 18, 1949

